Poly(lactide-<i>co</i>-glycolide)/Fibrin Gel Construct as a 3D Model to Evaluate Gene Therapy of Cartilage in Vivo

Combination of gene therapy with tissue engineering can enhance the interplay between cells and matrix, leading to better restoration and regeneration of tissues and organs in vivo. In this study the PLGA/fibrin gel hybrids were employed to load lipofectamine/pDNA-TGF-β1 complexes and mesenchymal stem cells (MSCs) (experimental group), acting as a cartilage-mimetic tissue platform. The gene complexes distributed more evenly in the hybrid scaffolds, whereas they adhered onto the pore walls of the PLGA sponges. The filled fibrin gel rendered gene release in a slower manner, too. Moreover, the fibrin gel entrapped MSCs and contributed to a higher cell loading density in the hybrid constructs. In vivo assay showed that in the defects implanted with the experimental constructs both gene and protein expression levels of TGF-β1 were significantly higher than those of the fibrin-free group at weeks 1, 3, and 6 after surgery. The full articular cartilage defects repaired by the experimental group for 12 w were resurfaced by neo-tissues with a similar thickness, cell arrangement, and color to the normal neighboring cartilage and abundant glycosaminoglycans